A limitation of bandwidth in the wireless network and the exponential rise in the high data rate requirement prompted the development of Massive Multiple-Input-Multiple-Output (MIMO) technique in 5G. Using this method the ever rising data rate can be met with the increment of the number of antennas. This comes at the price of energy consumption of higher amount, complex network setups and maintenance. Moreover a high-velocity user experiences unpredictable fluctuations in the channel condition that deteriorates the downlink performance. Therefore a proper number of antenna selection is of paramount importance. This issue has been addressed using different categories of algorithms but only for static users. In this study we proffer to implement antenna diversity in closed loop spatial multiplexing MIMO transmission scheme by operating more number of reception antennas than the number of transmission antennas for ameliorating the downlink performance of high-velocity users in case of single user MIMO technology. In general our results can be interpreted for large scale antenna systems like Massive MIMO even though a 4x4 MIMO system has been executed to carry out this study here. Additionally it shows great prospects for solving practical life problems like low data rate and call drops during handover to be experienced by cellular users traveling by high-speed transportation systems like Dhaka Metro Rail. The cell edge users are anticipated to get benefits from this method in case of SU-MIMO technology. The proposed method is expected to be easily implemented in the existing network structures with nominal difficulties.